The present invention relates, in general, to a technology for encoding a picture signal, and more particularly to a method of encoding and multiplexing picture signals corresponding to a plurality of an encoding and multiplexing apparatus utilizing the same.
In recent years, considerable progress has been made in the technology for encoding a picture signal, in particular the technology relating to the high efficiency-encoding of a moving picture signal. With respect to the encoding technology, international standardization has been promoted and also the number of systems for encoding a moving picture signal efficiently resulting from the various utilization forms has been increased.
In one of the high efficiency-encoding systems, there is the system request for encoding and multiplexing efficiently moving picture signals corresponding to a plurality of channels to transmit or record the resultant signals, and the development thereof has been advanced.
As for the apparatuses in the progress of development, there is well known the field a pick up apparatus (hereinafter, referred to as "an FPU apparatus" for short, when applicable) of the broadcasting system. However, the FPU apparatus as an example of the prior art operates to perform processing with an analog signal to transmit a picture signal. In this connection, only the picture signal corresponding to one channel is transmitted. Therefore, that prior art FPU apparatus cannot respond to the request in which the picture signals corresponding to a plurality of channels are wanted to be transmitted simultaneously.
For the purpose of responding to that request, there has been developed an apparatus in which the high efficiency-encoding technology is applied to the FPU apparatus in order to multiplex and transmit the signals corresponding to the three channels for example. In addition, this apparatus is such that the signals of the three channels are transmitted by the high efficiency-encoding transmission with the transmission capacity of the FPU apparatus made 15 Mbps for example, and also the transmission capacity of 5 Mbps is fixedly assigned to each channel in order to multiplex and transmit the picture signals of the three channels.
However, since in this case, normally, the different picture signals are input to the respective channels, a difference in level of redundancy may necessarily occur among the picture signals of the individual channels in some cases. In such cases, the transmission capacity of 5 Mbps may be insufficient for one channel, and the transmission capacity of 5 Mbps may be sufficient for another channel. In addition, the state in which the transmission capacity of 5 Mbps may be insufficient or sufficient with respect to each channel is changed all the time, and thus it is not fixed. For example, comparing a picture signal relating to a sport having violent movement and a picture signal relating to a silent scene with each other, it is clearly shown that the picture signal relating to the silent scene has a higher level of redundancy.
The fact that although the difference occurs among the levels of redundancy, the channels have the same assigned transmission rate results in the picture quality being remarkably degraded due to the encoding with respect to the channel having the lower level of redundancy and the degradation of the picture quality being extremely reduced beyond the necessity with respect to the channel having the higher level of redundancy.
Thus, there arises the problem that if the technology of interest is not advanced beyond the prior art high efficiency-encoding technology as described above, since the transmission rates are not assigned to the channels of the FPU apparatus so as to correspond to the levels of redundancy of the picture signals of the individual channels, the method of efficiently encoding and multiplexing picture signals is not realized by which the degradation of the picture quality can be efficiently reduced in all the channels.